has role independent continuant calcium ionophore polycyclic ether EC 3.1.3.16 (phosphoprotein phosphatase) inhibitor okadaic acid CHEBI:44658 A polycyclic ether that is produced by several species of dinoflagellates, and is known to accumulate in both marine sponges and shellfish. A polyketide, polyether derivative of a C<small>₃₈</small> fatty acid, it is one of the primary causes of diarrhetic shellfish poisoning (DSP). It is a potent inhibitor of specific protein phosphatases and is known to have a variety of negative effects on cells. marine metabolite